Optical transmit system

An optical transmit system, including a direct modulator configured to generate an optical signal, an optical amplifier coupled to the direct modulator configured to amplify the optical signal output by the direct modulator, and a stimulated Brillouin scattering component coupled to the optical amplifier configured to limit optical power of the optical signal output by the optical amplifier, where a stimulated Brillouin scattering threshold of the stimulated Brillouin scattering component is equal to minimum optical power of a part, which needs to be limited, of the optical signal output by the optical amplifier, and the stimulated Brillouin scattering component reflects, using a stimulated Brillouin scattering frequency difference, a part, which has optical power higher than the minimum optical power, of the optical signal output by the optical amplifier in order to limit outputting of this part of the optical signal.